State-of-the-art integrated circuits (ICs) for microprocessors routinely dissipate power densities on the order of 50 Watts/cm2. This large power is due to the localized heating of ICs operating at high frequencies, and must be managed for future high-frequency microelectronic applications. As the size of components and devices for ICs and other appliances becomes smaller, it becomes more difficult to provide heat dissipation and transport for such components and devices. A thermal conductor for a macro size thermal conductor is generally inadequate for use with a micro size component or device, in part due to scaling problems.
One consequence of increased component density in, and compactness of, ICs manifests itself in the form of locally high power consumption. An alarming rise in power density with respect to each advancing technology generation has been observed in mainstream microprocessor technologies. The need for addressing this problem is imperative for next-generation IC packaging technology. One potential solution is to find new packaging materials that exhibit high thermal conductivity and that can transfer heat from a local hot spot to a larger heat sink.
The cooling of an object by attaching it to a cold reservoir is normally limited by the heat transfer rate across the interface. Except for objects with atomically flat surfaces, practical objects normally have only a very small portion of surface in contact with other solid surfaces. Eutectic bonding materials or thermal conducting pastes/films are normally applied at the interface to increase the contact area. However, the thermal conductivities of these eutectic bonding materials are normally orders of magnitude lower than those of solid materials such as Cu and Si. The interface thus remains the bottleneck for heat dissipation. Metal film can be used to improve the thermal conductivity but is only applicable for high pressure loading.
What is needed is a compliant thermal interface material that efficiently and promptly dissipates or conducts heat from a micro size component or device, preferably down to nanometer scale systems, to a heat sink with a heat transfer rate that is comparable to rates for macro size components and devices. Preferably, the thermal conductor should be reusable and should work with any surface, rough or smooth.